Eradicating micrometastases with immune checkpoint blockade: Strike while the iron is hot.

Immune checkpoint blockade (ICB) is transforming treatment for many cancers. While ICB alone initially demonstrated efficacy in patients with metastatic melanoma, it has expanded to other types and to earlier-stage cancers. We describe ICB history, mechanisms underlying variation in response, and how ICB is being integrated into adjuvant and neoadjuvant treatment approaches.

Adoption of Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer.

Importance: Treatment of locally advanced rectal (LARC) cancer involves chemoradiation, surgery, and chemotherapy. The concept of total neoadjuvant therapy (TNT), in which chemoradiation and chemotherapy are administered prior to surgery, has been developed to optimize delivery of effective systemic therapy aimed at micrometastases. Objective: To compare the traditional approach of preoperative chemoradiation (chemoRT) followed by postoperative adjuvant chemotherapy with the more recent TNT approach for LARC. Design, Setting, and Participants: A retrospective cohort analysis using Memorial Sloan Kettering Cancer Center (MSK) records from 2009 to 2015 was carried out. A total of 811 patients who presented with LARC (T3/4 or node-positive) were identified. Exposures: Of the 811 patients, 320 received chemoRT with planned adjuvant chemotherapy and 308 received TNT (induction fluorouracil- and oxaliplatin-based chemotherapy followed by chemoRT). Main Outcomes and Measures: Treatment and outcome data for the 2 cohorts were compared. Dosing and completion of prescribed chemotherapy were assessed on the subset of patients who received all therapy at MSK. Results: Of the 628 patients overall, 373 (59%) were men and 255 (41%) were women, with a mean (SD) age of 56.7 (12.9) years. Of the 308 patients in the TNT cohort, 181 (49%) were men and 127 (49%) were women. Of the 320 patients in the chemoRT with planned adjuvant chemotherapy cohort, 192 (60%) were men and 128 (40%) were women. Patients in the TNT cohort received greater percentages of the planned oxaliplatin and fluorouracil prescribed dose than those in the chemoRT with planned adjuvant chemotherapy cohort. The complete response (CR) rate, including both pathologic CR (pCR) in those who underwent surgery and sustained clinical CR (cCR) for at least 12 months posttreatment in those who did not undergo surgery, was 36% in the TNT cohort compared with 21% in the chemoRT with planned adjuvant chemotherapy cohort. Conclusions and Relevance: Our findings provide additional support for the National Comprehensive Cancer Network (NCCN) guidelines that categorize TNT as a viable treatment strategy for rectal cancer. Our data suggest that TNT facilitates delivery of planned systemic therapy. Long-term follow-up will determine if this finding translates into improved survival. In addition, given its high CR rate, TNT may facilitate nonoperative treatment strategies aimed at organ preservation.

Micrometastatic Drug Screening Platform Shows Heterogeneous Response to MAP Chemotherapy in Osteosarcoma Cell Lines.

BACKGROUND: Approximately 80% of patients with osteosarcoma harbor subclinical pulmonary micrometastases at diagnosis. Conventional chemotherapy includes methotrexate, doxorubicin, and cisplatin (MAP); however, this regimen and thus overall survival (60%-70%) have remained largely unchanged for 30 years. It therefore is necessary to identify novel therapeutics targeting the metastatic progression of osteosarcoma. QUESTIONS/PURPOSES: This laboratory study explored application of osteosarcoma spheroids (sarcospheres) for drug screening with the following purposes: (1) to characterize sarcosphere size; (2) to establish accurate measurement of sarcosphere growth; (3) to confirm sarcosphere uniformity; and (4) to apply the platform to evaluate MAP chemotherapy. METHODS: Sarcospheres were first characterized to establish accurate measurement of sarcosphere growth and uniform production. The refined platform then was applied to evaluate MAP chemotherapy to validate its use in drug screening. Sarcospheres were generated from highly metastatic human cell lines (143B, MG-63.3, and LM7) by centrifugation to form three-dimensional aggregates modeling micrometastases. Sarcospheres were matured for 24 hours and then incubated with or without drug from Days 0 to 2. Size was assessed by diameter and volume using brightfield microscopy. Growth was measured by volume and resazurin reduction in viable cells. Sarcosphere uniformity was assessed by diameter and resazurin reduction at Day 0 and the Z' factor, a measure of assay suitability for high-throughput screening, was calculated at Day 2. Sarcospheres were treated with individual MAP agents (0 to 1000 µmol/L) to determine concentrations at which 50% of growth from Days 0 to 2 was inhibited (GIC50). Cell lines resistant to MAP in sarcospheres were treated in monolayer for comparison. RESULTS: Sarcosphere diameter and growth from Days 0 to 2 were quantitatively dependent on the number of cells seeded and the cell line used. Accurate measurement of growth occurred after resazurin incubation for 6 hours, without EDTA-mediated permeabilization, and was correlated with the number of cells seeded and sarcosphere volume for 143B (Spearman's r: 0.98; p < 0.001), MG-63.3 (0.99; p < 0.001), and LM7 (0.98; p < 0.001). Sarcospheres met established criteria for screening applications as mean Z' factors were greater than 0.5 for all cell lines. Response to MAP therapy was cell line-dependent, because MG-63.3 and LM7 sarcospheres exhibited greater than 2000-fold resistance to methotrexate (GIC50 = 88 ± 36 µmol/L and 174 ± 16 µmol/L, respectively) compared with the 143B cell line (GIC50 = 0.04 ± 0.01 µmol/L; p < 0.001 for MG-63.3 and LM7). MG-63.3 monolayers were more sensitive to methotrexate (GIC50 = 0.01 ± 0.01 µmol/L; p < 0.001) than MG-63.3 sarcospheres, whereas LM7 monolayers remained chemoresistent (GIC50 not reached). CONCLUSIONS: This study developed and validated a drug screening platform for progression of osteosarcoma micrometastases. It also highlights heterogeneity among osteosarcoma cell lines. These findings appear to reflect known patient-to-patient heterogeneity and underscore the importance of evaluating multiple tumor models when testing drugs for the treatment of osteosarcoma. CLINICAL RELEVANCE: The described approach is a promising starting point for drug screening in osteosarcoma because it is tailored to evaluate micrometastatic disease. A reliable and rapid method to identify novel therapeutics is critical to improve stagnant outcomes for patients with osteosarcoma.

Management of the lateral neck in well differentiated thyroid cancer.

Lateral neck lymph node metastases in well differentiated thyroid cancer are common, ranging from 30% to 60%, with the majority of these foci identifiable only as microscopic deposits. A skilled ultrasound evaluation of the lymph nodes in the lateral neck is recommended for all patients presenting with newly diagnosed thyroid cancer undergoing surgical management. Ultrasound guided fine needle aspiration biopsy may be used to cytologically confirm suspected lateral neck nodal metastases prior to surgery. For patients with large volume nodal disease, extranodal extension, or multiple nodal metastases, computed tomography (CT) scan of the neck with contrast is an important additional imaging modality to accurately localize disease prior to surgery. Primary surgical management for lateral neck disease typically includes lateral neck dissection in conjunction with total thyroidectomy. Postoperative adjuvant radioactive iodine is typically recommended for patients with clinically evident nodal metastases, or for those with over 5 micrometastatic nodes. In the recurrent or persisting disease setting, complete surgical resection of local and regional disease remains the main treatment approach. However, sub-centimeter nodal disease may take an indolent course, and active surveillance may be a reasonable approach in selected clinical circumstances. Conversely, external beam radiation therapy (EBRT) may be considered for scenarios with unresectable disease, or microscopic residual disease following surgery in a clinically unfavorable setting. Two multi-kinase inhibitors (sorafenib and lenvatinib) are now FDA approved for treatment of RAI refractory thyroid cancer and now play an important role in the management of progressive, metastatic and surgically incurable disease.

Use of axillary lymph node dissection (ALND) in patients with micrometastatic breast cancer.

BACKGROUND: Sentinel lymph node (SLN) biopsy is the current prognostic tool for clinically node-negative breast cancer patients. If the SLN reveals macrometastasis, axillary lymph node dissection (ALND) is recommended. However, the use of ALND in patients with micrometastasis is debated. The objective of this study was to assess the utilization of ALND in the treatment of micrometastatic breast cancer. METHODS: An IRB approved, retrospective study of a pooled dataset of breast cancer patients with micrometastatic disease on SLN biopsy was performed. Patients diagnosed from 1999-2016 were identified via query of a single-institution National Comprehensive Cancer Network (NCCN) breast cancer database as well as a prospective tumor board. RESULTS: A total of 91 patients were diagnosed with micrometastatic nodal disease. The median age at diagnosis was 56 y (range: 31-85); median follow-up time was 47 mo (range: 0-203 mo). 42/91(46.2%) patients had ALND of which 37/42 (88.1%) were a second operation; 3/42(7.1%) patients had additional positive nodes found at ALND. 44/91 (48.4%) patients received radiation. 7/91 (7.7%) patients had a recurrence, 5/7 local, including one axillary (2.1%; patient declined ALND). CONCLUSIONS: Given that the risk of lymphedema after ALND ranges between 20%-53%, the morbidity of ALND may far exceed the likelihood of detecting further nodal involvement in women with micrometastatic disease: 7.1% in this series.

Toxicity evaluation of magnetic hyperthermia induced by remote actuation of magnetic nanoparticles in 3D micrometastasic tumor tissue analogs for triple negative breast cancer.

Magnetic hyperthermia as a treatment modality is acquiring increased recognition for loco-regional therapy of primary and metastatic lung malignancies by pulmonary delivery of magnetic nanoparticles (MNP). The unique characteristic of magnetic nanoparticles to induce localized hyperthermia in the presence of an alternating magnetic field (AMF) allows for preferential killing of cells at the tumor site. In this study we demonstrate the effect of hyperthermia induced by low and high dose of MNP under the influence of an AMF using 3D tumor tissue analogs (TTA) representing the micrometastatic, perfusion independent stage of triple negative breast cancer (TNBC) that infiltrates the lungs. While application of inhalable magnetic nanocomposite microparticles or magnetic nanocomposites (MnMs) to the micrometastatic TNBC model comprised of TTA generated from cancer and stromal cells, showed no measureable adverse effects in the absence of AMF-exposure, magnetic hyperthermia generated under the influence of an AMF in TTA incubated in a high concentration of MNP (1 mg/mL) caused significant increase in cellular death/damage with mechanical disintegration and release of cell debris indicating the potential of these inhalable composites as a promising approach for thermal treatment of diseased lungs. The novelty and significance of this study lies in the development of methods to evaluate in vitro the application of inhalable composites containing MNPs in thermal therapy using a physiologically relevant metastatic TNBC model representative of the microenvironmental characteristics in secondary lung malignancies.

Micrometastasis Volume in Lymph Nodes Determines Disease Recurrence Rate of Stage II Colorectal Cancer: A Prospective Multicenter Trial.

PURPOSE: We reported in a retrospective study that the presence of micrometastasis in lymph nodes, when assessed by carcinoembryonic antigen (CEA)-specific RT-PCR, is a significant prognostic factor in stage II colorectal cancer. The aim of this study was to clarify the clinical value of micrometastasis in a prospective multicenter trial. EXPERIMENTAL DESIGN: From November 2001 to December 2005, a total of 419 colorectal cancer cases were preoperatively registered at a central data center. Of them, 315 node-negative stage II colorectal cancer cases were enrolled. After RNA quality check, 304 colorectal cancer cases were analyzed for CEA mRNA in lymph nodes by both conventional RT-PCR (a band method) and quantitative RT-PCR. Long-term prognosis of the patients was determined by each method. RESULTS: A positive band for CEA mRNA was detected in 73 (24.0%) of 304 patients. Postoperative adjuvant chemotherapy was applied in 31 CEA band-positive cases with an oral 5-fluorouracil derivative HCFU (1-hexylcarbamoyl-5-fluorouracil) for 1 year, whereas chemotherapy was not administered to CEA band-negative group. Multivariate Cox regression analyses revealed that a high micrometastasis volume (high MMV, n = 95) was an independent poor prognostic factor for 5-year disease-free survival (DFS; P = 0.001) and 5-year overall survival (OS; P = 0.016). CONCLUSIONS: This prospective clinical trial demonstrates that micrometastasis volume is a useful marker in identifying patients who are at high or low risk for recurrence of stage II colorectal cancer. Clin Cancer Res; 22(13); 3201-8. ©2016 AACR.

[Huikangling Tablet Intervened Peripheral Blood Micrometastasis of Differentiated Thyroid Carcinoma].

OBJECTIVE: To observe the clinical effect of Huikangling Tablet (HT, extracted from Scabrous Patrinia root) on peripheral blood micrometastasis of differentiated thyroid carcinoma (DTC) patients. METHODS: Totally 87 DTC patients with positive micrometastasis were randomly assigned to the treatment group (45 cases) and the control group (42 cases). DTC endocrine inhibition treatment standards were executed in all patients. They all took levothyroxine sodium (50 microg/tablet, from low dose, 25 microg each time, once per day, 0.5 h before breakfast), and its dosage was gradually added one week later. The dosage was adjusted according to tested results of TSH combined recurrence risk stratification and endocrine suppression induced adverse reactions risk stratification. Patients in the treatment group took HT (0.4 g per tablet, 3 tablets each time, three times per day for a total of 12 weeks) combined TSH suppression therapy, while those in the control group only received TSH suppression therapy. Peripheral micrometastatic cytokeratin 19 (CK19) and polymorphic epithelial mucin1 (MUC1) were detected by FCM at week 4 and 12. Meanwhile, distant metastasis and adverse reactions were observed. RESULTS: After 4-week treatment positive micrometastasis was shown in 18 cases (40%) of the treatment group and 29 cases (69%) in the control group with statistical difference (chi2 = 5.68, P < 0.05). After 12-week treatment positive micrometastasis was shown in 7 cases (15.6%) of the treatment group and 17 cases (44.7%) in the control group with statistical difference (chi2 = 8.49, P < 0.01). Pulmonary metastasis occurred in 2 cases and bone metastasis in 1 case of the control group at follow-ups. Cervical lymph node metastasis without accompanied recurrence of thyroid cancer occurred in one case of the treatment group. No obvious liver or renal abnormalities occurred. CONCLUSION: HT inhibited peripheral blood micrometastasis of DTC patients and its mechanism needed to be further studied.

Huikangling Tablet Intervened Peripheral Blood Micrometastasis of Differentiated Thyroid Carcinoma / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To observe the clinical effect of Huikangling Tablet (HT, extracted from Scabrous Patrinia root) on peripheral blood micrometastasis of differentiated thyroid carcinoma (DTC) patients.</p><p><b>METHODS</b>Totally 87 DTC patients with positive micrometastasis were randomly assigned to the treatment group (45 cases) and the control group (42 cases). DTC endocrine inhibition treatment standards were executed in all patients. They all took levothyroxine sodium (50 microg/tablet, from low dose, 25 microg each time, once per day, 0.5 h before breakfast), and its dosage was gradually added one week later. The dosage was adjusted according to tested results of TSH combined recurrence risk stratification and endocrine suppression induced adverse reactions risk stratification. Patients in the treatment group took HT (0.4 g per tablet, 3 tablets each time, three times per day for a total of 12 weeks) combined TSH suppression therapy, while those in the control group only received TSH suppression therapy. Peripheral micrometastatic cytokeratin 19 (CK19) and polymorphic epithelial mucin1 (MUC1) were detected by FCM at week 4 and 12. Meanwhile, distant metastasis and adverse reactions were observed.</p><p><b>RESULTS</b>After 4-week treatment positive micrometastasis was shown in 18 cases (40%) of the treatment group and 29 cases (69%) in the control group with statistical difference (chi2 = 5.68, P < 0.05). After 12-week treatment positive micrometastasis was shown in 7 cases (15.6%) of the treatment group and 17 cases (44.7%) in the control group with statistical difference (chi2 = 8.49, P < 0.01). Pulmonary metastasis occurred in 2 cases and bone metastasis in 1 case of the control group at follow-ups. Cervical lymph node metastasis without accompanied recurrence of thyroid cancer occurred in one case of the treatment group. No obvious liver or renal abnormalities occurred.</p><p><b>CONCLUSION</b>HT inhibited peripheral blood micrometastasis of DTC patients and its mechanism needed to be further studied.</p>

Selective treatment and monitoring of disseminated cancer micrometastases in vivo using dual-function, activatable immunoconjugates.

Drug-resistant micrometastases that escape standard therapies often go undetected until the emergence of lethal recurrent disease. Here, we show that it is possible to treat microscopic tumors selectively using an activatable immunoconjugate. The immunoconjugate is composed of self-quenching, near-infrared chromophores loaded onto a cancer cell-targeting antibody. Chromophore phototoxicity and fluorescence are activated by lysosomal proteolysis, and light, after cancer cell internalization, enabling tumor-confined photocytotoxicity and resolution of individual micrometastases. This unique approach not only introduces a therapeutic strategy to help destroy residual drug-resistant cells but also provides a sensitive imaging method to monitor micrometastatic disease in common sites of recurrence. Using fluorescence microendoscopy to monitor immunoconjugate activation and micrometastatic disease, we demonstrate these concepts of "tumor-targeted, activatable photoimmunotherapy" in a mouse model of peritoneal carcinomatosis. By introducing targeted activation to enhance tumor selectively in complex anatomical sites, this study offers prospects for catching early recurrent micrometastases and for treating occult disease.

Colon cancer cells escape 5FU chemotherapy-induced cell death by entering stemness and quiescence associated with the c-Yes/YAP axis.

PURPOSE: Metastasis and drug resistance are the major limitations in the survival and management of patients with cancer. This study aimed to identify the mechanisms underlying HT29 colon cancer cell chemoresistance acquired after sequential exposure to 5-fluorouracil (5FU), a classical anticancer drug for treatment of epithelial solid tumors. We examined its clinical relevance in a cohort of patients with colon cancer with liver metastases after 5FU-based neoadjuvant chemotherapy and surgery. RESULTS: We show that a clonal 5F31 cell population, resistant to 1 µmol/L 5FU, express a typical cancer stem cell-like phenotype and enter into a reversible quiescent G0 state upon reexposure to higher 5FU concentrations. These quiescent cells overexpressed the tyrosine kinase c-Yes that became activated and membrane-associated upon 5FU exposure. This enhanced signaling pathway induced the dissociation of the Yes/YAP (Yes-associated protein) molecular complex and depleted nuclear YAP levels. Consistently, YES1 silencing decreased nuclear YAP accumulation and induced cellular quiescence in 5F31 cells cultured in 5FU-free medium. Importantly, YES1 and YAP transcript levels were higher in liver metastases of patients with colon cancer after 5FU-based neoadjuvant chemotherapy. Moreover, the YES1 and YAP transcript levels positively correlated with colon cancer relapse and shorter patient survival (P < 0.05 and P < 0.025, respectively). CONCLUSIONS: We identified c-Yes and YAP as potential molecular targets to eradicate quiescent cancer cells and dormant micrometastases during 5FU chemotherapy and resistance and as predictive survival markers for colon cancer.

Pazopanib inhibits the activation of PDGFRß-expressing astrocytes in the brain metastatic microenvironment of breast cancer cells.

Brain metastases occur in more than one-third of metastatic breast cancer patients whose tumors overexpress HER2 or are triple negative. Brain colonization of cancer cells occurs in a unique environment, containing microglia, oligodendrocytes, astrocytes, and neurons. Although a neuroinflammatory response has been documented in brain metastasis, its contribution to cancer progression and therapy remains poorly understood. Using an experimental brain metastasis model, we characterized the brain metastatic microenvironment of brain tropic, HER2-transfected MDA-MB-231 human breast carcinoma cells (231-BR-HER2). A previously unidentified subpopulation of metastasis-associated astrocytes expressing phosphorylated platelet-derived growth factor receptor ß (at tyrosine 751; p751-PDGFRß) was identified around perivascular brain micrometastases. p751-PDGFRß(+) astrocytes were also identified in human brain metastases from eight craniotomy specimens and in primary cultures of astrocyte-enriched glial cells. Previously, we reported that pazopanib, a multispecific tyrosine kinase inhibitor, prevented the outgrowth of 231-BR-HER2 large brain metastases by 73%. Here, we evaluated the effect of pazopanib on the brain neuroinflammatory microenvironment. Pazopanib treatment resulted in 70% (P = 0.023) decrease of the p751-PDGFRß(+) astrocyte population, at the lowest dose of 30 mg/kg, twice daily. Collectively, the data identify a subpopulation of activated astrocytes in the subclinical perivascular stage of brain metastases and show that they are inhibitable by pazopanib, suggesting its potential to prevent the development of brain micrometastases in breast cancer patients.

RAF-targeted therapy for hepatocellular carcinoma in the regenerating liver.

BACKGROUND: Post-operative liver regeneration may contribute to tumor recurrence. There is a theoretical need for an adjuvant therapy that can suppress tumor growth without adversely affecting post-operative liver regeneration. OBJECTIVE: To evaluate the effect of RAF inhibitor Sorafenib on cell viability and proliferation of hepatoma cells and hepatocytes in vitro and in an in vivo rat model. METHODS: Cell viability, DNA synthesis, and RAF/MAPK kinase activity in the primary hepatocyte and hepatoma cell lines were investigated after Sorafenib exposure. Sequence analysis of the B-RAF gene in hepatic cells was determined. Tumor markers were compared within the rats after 70% hepatectomy with or without daily oral gavages of Sorafenib. Liver regeneration was assessed by liver function tests and proliferation markers. RESULTS: Primary hepatocytes showed higher cell viability, proliferation rate, and stronger RAF/MAPK kinase activity compared with hepatoma cell lines. The in vivo tumor volumes, size, and metastases were significantly decreased (P < 0.05) whereas no significant change in liver regeneration related to Sorafenib exposure was found (P > 0.05). B-RAF V600E mutation was not detected neither in the hepatic cells nor untransformed hepatocytes. CONCLUSIONS: The RAF targeted inhibitor can reduce tumor growth without retarding liver regeneration in this experiment.

Bilobar colorectal liver metastases: a new model for preclinical studies.

SUMMARY: This study aimed to develop a new model of colorectal liver metastases (LM) in the rat. Both single macroscopic and multiple bilobar microscopic LM were investigated, as this closely resembled the human situation, before right hepatectomy was performed for 'single' right LM. The single macroscopic LM was elicited by direct injection of DHD/K12 colorectal cancer cells under the capsule of the median liver lobe in immunocompetent BDIX rats. The bilobar micrometastases were elicited by intraportal injection of DHD/K12 cells. A preliminary protocol was conducted to assess the dose of cells required to inject in to the portal vein, using 10(6) , 2 × 10(6) and 3 × 10(6) DHD/K12 cells (n = 15 rats). The resultant protocol for the experimental model used intraportal injection of 10(6) DHD/K12 cells and direct injections of 0.5 × 10(6) , 10(6) and 1.5 × 10(6) DHD/K12 cells (n = 15 rats). For both protocols, BDIX rats were sacrificed at day 30 after injection. The preliminary protocol showed that intraportal injection of 10(6) DHD/K12 cells was associated with bilobar micrometastases of 0.8 mm mean diameter at day 30. The main protocol assessed that direct injection of 0.5 × 10(6) under the liver median lobe capsule and intraportal injection of 10(6) DHD/K12 cells were associated at day 30 with a single macroscopic metastasis confined to a liver lobe and bilobar micrometastases, without peritoneal carcinomatosis or lung metastasis. Thus we have developed a new experimental model of bilobar colorectal LM including both macro- and microscopic colorectal LMs, which mimics the human situation and which will be useful in preclinical studies.

Histone deacetylase inhibitors induce growth arrest and differentiation in uveal melanoma.

PURPOSE: Metastasis is responsible for the death of most cancer patients, yet few therapeutic agents are available which specifically target the molecular events that lead to metastasis. We recently showed that inactivating mutations in the tumor suppressor gene BAP1 are closely associated with loss of melanocytic differentiation in uveal melanoma (UM) and metastasis. The purpose of this study was to identify therapeutic agents that reverse the phenotypic effects of BAP1 loss in UM. EXPERIMENTAL DESIGN: In silico screens were done to identify therapeutic compounds predicted to differentiate UM cells using Gene Set Enrichment Analysis and Connectivity Map databases. Valproic acid (VPA), trichostatin A, LBH-589, and suberoylanilide hydroxamic acid were evaluated for their effects on UM cells using morphologic evaluation, MTS viability assays, bromodeoxyuridine incorporation, flow cytometry, clonogenic assays, gene expression profiling, histone acetylation and ubiquitination assays, and a murine xenograft tumorigenicity model. RESULTS: Histone deacetylase (HDAC) inhibitors induced morphologic differentiation, cell-cycle exit, and a shift to a differentiated, melanocytic gene expression profile in cultured UM cells. VPA inhibited the growth of UM tumors in vivo. CONCLUSIONS: These findings suggest that HDAC inhibitors may have therapeutic potential for inducing differentiation and prolonged dormancy of micrometastatic disease in UM.

The influence of toxicity constraints in models of chemotherapeutic protocol escalation.

The prospect of exploiting mathematical and computational models to gain insight into the influence of scheduling on cancer chemotherapeutic effectiveness is increasingly being considered. However, the question of whether such models are robust to the inclusion of additional tumour biology is relatively unexplored. In this paper, we consider a common strategy for improving protocol scheduling that has foundations in mathematical modelling, namely the concept of dose densification, whereby rest phases between drug administrations are reduced. To maintain a manageable scope in our studies, we focus on a single cell cycle phase-specific agent with uncomplicated pharmacokinetics, as motivated by 5-Fluorouracil-based adjuvant treatments of liver micrometastases. In particular, we explore predictions of the effectiveness of dose densification and other escalations of the protocol scheduling when the influence of toxicity constraints, cell cycle phase specificity and the evolution of drug resistance are all represented within the modelling. For our specific focus, we observe that the cell cycle and toxicity should not simply be neglected in modelling studies. Our explorations also reveal the prediction that dose densification is often, but not universally, effective. Furthermore, adjustments in the duration of drug administrations are predicted to be important, especially when dose densification in isolation does not yield improvements in protocol outcomes.

Use of RT-PCR for Cytokeratin 19 to Detect Micrometastases in Bone Marrow of Follow-up Patients with Breast Cancer after Surgery

PURPOSE: We have previously reported that the reverse transcriptase-polymerase chain reaction (RT-PCR) for cytokeratin 19 (CK 19) is a highly sensitive and specific method for detecting micrometas tases in the bone marrow of patients with primary breast cancer. Thus, we conducted this study to identify occult metastatic cells in the bone marrow of follow-up patients with breast cancer by using the RT-PCR for cytokeratin 19 after surgery. METHODS: We studied 42 patients with breast cancer who had no evidence of relapse, 3 patients who had a local relapse, and 7 patients who had distant metastases. Bone-marrow aspirates were taken from the single posterior iliac crest under local anesthesia anesthesia at a median of 45 months after surgery. RT-PCR for CK19 was done by using two 30-cycle rounds with nested primers. RESULTS: Occult metastases were found in 23% of the 52 breast-cancer patients. None of the bone-marrow aspirates showed any evidence of tumor involvement by using conventional cytology. RT- PCR was positive for CK 19 in 19% of the 42 patients without relapse, and in 40% of the 10 patients with local or distant relapse. CONCLUSION: RT-PCR for CK 19 is a sensitive method for detecting tumor cells in the bone marrow of follow-up patients with breast cancer after surgery. This assay may be useful in detecting metastastic disease, as well as in monitoring the effectiveness of systemic therapy. However, a large study with long-term follow-up is required in order to clarify its clinical significance and usefulness.

The Detection of Micrometastasis in Sentinel Nodes of Breast Cancer by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR)

BACKGROUND: The accurate staging of patients with breast cancer is essential to its management and prognosis. Sentinel node biopsy appears to offer an alternative to routine axillary lymph node dissection for staging breast cancer patients. Current method of routine histopathologic analysis of dissected lymph nodes may be inadequate because up to 30% of patients free of lymph node metastases develop a relapse in 5 to 10 years. Recently, the development of amplification of MUC1 mRNA and keratin 19 mRNA by RT-PCR for detection of micrometastases in breast cancer has been shown to be a sensitive and useful diagnostic method. This study was performed to evaluate the usefulness of MUC1 mRNA and keratin 19 mRNA markers by RT-PCR to detect micrometastases in frozen sections of sentinel lymph nodes from breast cancer patients and to identify which histopathologic prognostic factors were related to RT-PCR detected micrometastases. METHODS: The incidence of axillary micrometastases in 15 sentinel lymph node specimens from 15 patients who underwent breast cancer surgery with sentinel lymphadenectomy was from June 1999 to July 1999 was studied. Complete axillary dissection was made in all of the patients. Each sentinel lymph node specimen was examined by hematoxylin and eosin (H&E) staining, immunohistochemical cyto keratin (IHC) staining and RT-PCR on adjacent sections to determine the expression of the mRNA tumor marker of MUC1 and keratin 19. All of the dissected lymph nodes were examined by serial sectioning. RESULTS: Fourteen out of 15 sentinel lymph nodes were histologically negative in usual H&E staining. Serial sectioning, immunohistochemical (IHC) staining for cytokeratin demonstrated micrometastases in one, two histologically negative sentinel nodes, respectively, and MUC1 mRNA was detected in all of them. Of the 12 sentinel lymph nodes that were diagnosed to be devoid of micrometastases by IHCand serial sectioning, MUC1 mRNA was expressed in 6 nodes, indicating the presence of micrometastases. Micrometastases detected by RT-PCR were significantly correlated with tumor size, expression of p53 and negative PR in conventionally lymph node-negative staged patients. CONCLUSION: The MUC1 mRNA RT-PCR was more sensitive than immunohistochemistry and serial sectioning for the detection of micrometastases in axillary lymph nodes, but keratin 19 was not specific. Sentinel lymph node biopsy with RT-PCR is a more useful means of detecting micrometastases and may have a role in identifying a group of patients who will benefit from earlier adjuvant chemotherapy, but the prognostic significance must be determined after a longer follow-up.